JP5906776B2 - Turbo molecular pump - Google Patents

Description

  The present invention relates to a turbomolecular pump having a cylindrical portion of fiber reinforced plastic adhesively bonded to a rotor.

  Conventionally, a turbomolecular pump has an all-blade type turbomolecular pump having only rotor blades and fixed blades, a turbo pump stage composed of rotor blades and fixed blades, and a screw groove in the rotation side cylinder portion or the fixed side cylinder portion. There is a hybrid turbomolecular pump consisting of a formed drug pump stage.

  In the composite turbo molecular pump, generally, the rotation-side cylindrical portion of the drag pump stage is formed integrally with the rotor blade, and a metal material such as an aluminum alloy is used as the material thereof. On the other hand, in order to reduce the rotor weight, a configuration is known in which the rotation-side cylindrical portion of the drag pump stage is formed of a carbon fiber reinforced composite material (CFRP) or the like having a low specific gravity (for example, see Patent Document 1).

  In general, the CFRP cylindrical portion is connected to the aluminum rotor by a fitting structure in which the CFRP cylindrical portion is a hole and the rotor side is an axis, and bonding is used for bonding. CFRP has a lower specific gravity, a higher Young's modulus, and a lower coefficient of thermal expansion than aluminum. Therefore, expansion due to centrifugal force and thermal expansion is small during rotation. For this reason, the surface pressure from the rotor tends to increase during rotation, and the tightening margin is set small in order to prevent excessive surface pressure from being generated during rotation.

Japanese Patent Laid-Open No. 7-4383

  By the way, since the coefficient of thermal expansion of the CFRP cylindrical portion and the rotor is different as described above, the coupling between the CFRP cylindrical portion and the rotor is loosened when exposed to a temperature lower than expected, such as in cold districts or air transportation. there is a possibility. If an impact or vibration is applied in such a loose state, the CFRP cylindrical portion may be displaced with respect to the rotor, and the balance of the rotating body may be deteriorated.

The turbo molecular pump according to the first aspect of the present invention includes a metal rotor having a plurality of stages of rotor blades and a ring portion formed at one end in the axial direction, and alternately arranged in the axial direction with respect to the rotor blades. A plurality of fixed wings, a cylindrical portion formed of fiber-reinforced plastic and bonded to be inserted into the ring portion, and a rotating cylindrical portion disposed on the outer peripheral side of the cylindrical portion via a gap. The adhesive portion of the ring portion is filled with an adhesive and has at least one groove for preventing the rotation of the rotating cylindrical portion.
According to a second aspect of the present invention, in the turbo molecular pump according to the first aspect, two types of grooves having different angles with respect to the axial direction are formed in the ring portion.
According to a third aspect of the present invention, in the turbo molecular pump according to the second aspect, one of the two types of grooves is a ring groove that goes around the ring portion.
According to a fourth aspect of the present invention, in the turbo molecular pump according to the first aspect, the groove is an inclined groove inclined with respect to the axial direction, and the ring portion includes a groove forming area in which the inclined groove is formed, and a groove forming area. And an inlay portion region that is provided in contact with both ends in the axial direction and functions as an inlay portion with respect to the rotating cylindrical portion.
According to a fifth aspect of the present invention, in the turbomolecular pump according to the first aspect, the groove is inclined with respect to the axial direction, and the groove depth decreases from one end to the other end in the extending direction of the groove. The ring part is formed, and the ring part is provided in contact with the groove forming area where the oblique groove is formed and the axial direction of the groove forming area on one end side of the oblique groove, and as an inlay part with respect to the rotating cylindrical part And a functioning inlay portion region.

  According to the present invention, even if the FRP rotating cylindrical portion may be loosened at a low temperature or the like, the rotating cylindrical portion is not displaced from the rotor ring portion.

It is a figure which shows schematic structure of a turbo-molecular pump. FIG. 3 is a diagram showing a first example of a joint structure between a rotating cylindrical portion 32 and a rotor 30. It is a figure which shows the case where the diagonal grooves 300 and 301 are made to cross | intersect. It is a figure which shows the case where a diagonal groove | channel and a ring groove | channel are combined. It is a figure which shows the 2nd example of joining structure. It is a figure which shows the 3rd example of joining structure. It is a figure which shows the 4th example of joining structure.

  Embodiments for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a magnetic levitation turbomolecular pump. In this embodiment, a magnetic levitation type turbo molecular pump will be described as an example. However, the present invention can be similarly applied to a rotor of a turbo molecular pump that is not a magnetic levitation type.

  A turbo molecular pump 1 is connected to a power supply device (not shown) and is driven and controlled by the power supply device. The shaft 31 to which the rotor 30 is attached is supported in a non-contact manner by electromagnets 37, 38 and 39 provided on the base 20. The electromagnet 39 constituting the axial magnetic bearing is arranged so as to sandwich the rotor disk 35 provided at the lower end of the shaft 31 in the axial direction. The flying position of the shaft 31 is detected by radial displacement sensors 27 and 28 and an axial displacement sensor 29.

  The rotating body (rotor 30 and shaft 31) magnetically levitated so as to be freely rotatable by the magnetic bearing is driven to rotate at high speed by the motor. For example, a brushless DC motor is used as the motor 36. The motor stator 36a is provided on the base 20, and the motor rotor (permanent magnet) 36b is provided on the shaft 31 side.

  The rotation of the rotor 30 is detected by the rotation sensor 33. A sensor target 34 is provided at the lower end of the shaft 31 that is rotationally driven by the motor 36. The sensor target 34 rotates integrally with the shaft 31. The axial displacement sensor 29 and the rotation sensor 33 described above are disposed at positions facing the lower surface of the sensor target 34. 26a and 26b are emergency mechanical bearings, and the shaft 31 is supported by these mechanical bearings 26a and 26b when the magnetic bearing is not operating.

  The turbo molecular pump 1 shown in FIG. 1 has a turbo pump stage composed of a rotating blade 30b and a fixed blade 22, and a drag pump stage (thread groove pump) composed of a rotating cylindrical portion 32 and a screw stator 24. doing. Here, a screw groove is formed on the screw stator 24 side, but a screw groove may be formed on the rotating cylindrical portion 32 side. The rotor 30 made of aluminum alloy is formed with a plurality of stages of rotating blades 30b. The plurality of stages of fixed blades 22 are alternately arranged with the rotary blades 30b in the axial direction. Each fixed wing 22 is placed on the base 20 via the spacer ring 23. When the fixing flange 21c of the pump casing 21 is fixed to the base 20 with a bolt, the stacked spacer ring 23 is sandwiched between the base 20 and the pump casing 21, and the fixed blade 22 is positioned.

  A ring portion 30a is formed at the lower end in the axial direction of the rotor 30, and the rotary cylindrical portion 32 described above is bonded and bonded so that the upper end portion thereof is extrapolated to the ring portion 30a. A screw stator 24 that is a fixed-side drag pump stage is provided on the outer peripheral side of the rotating cylindrical portion 32. The screw stator 24 is attached to the base 20 so that a predetermined gap is formed between the screw stator 24 and the rotating cylindrical portion 32.

  For the rotating cylindrical portion 32, fiber reinforced plastics (FRP: Fiber Reinforced Plastics) such as CFRP and GFRP having a low specific gravity are used to reduce the weight of the rotor. As a base material (matrix) of fiber reinforced plastic, generally, thermosetting resin such as unsaturated polyester is often used, and epoxy resin, polyamide resin, phenol resin, and the like are also used. Details of the joint structure between the rotating cylindrical portion 32 and the rotor 30 will be described later.

  The base 20 is provided with an exhaust port 25, and a back pump is connected to the exhaust port 25. When the rotor 30 is magnetically levitated and driven at high speed by the motor 36, the gas molecules on the intake port 21a side are exhausted to the exhaust port 25 side.

  FIG. 2 is a diagram illustrating a first example of a joint structure (portion indicated by a symbol A in FIG. 1) between the rotating cylindrical portion 32 and the rotor 30. FIG. 2A is an enlarged view of a portion of the ring portion 30a of the rotor 30, and FIG. 2B shows a cross section of a joint portion between the rotor 30 and the rotating cylindrical portion 32. As shown in FIG. As shown in FIG. 2A, two types of oblique grooves 300 and 301 are formed on the outer peripheral surface of the ring portion 30a. In the example shown in FIG. 2A, a plurality of oblique grooves 300 and 301 are formed at predetermined intervals on the outer peripheral surface of the ring portion, but only one set of the oblique grooves 300 and 301 may be formed. However, from the viewpoint of balance, it is preferable to arrange the oblique grooves 300 and 301 at equal intervals over one circumference.

  The oblique groove 300 and the oblique groove 301 have different angles with respect to the axial direction J. In the example shown in FIG. 2, the oblique groove 300 is inclined with respect to the axial direction J by an angle θ. On the other hand, the angle θ1 of the oblique groove 301 with respect to the axial direction J is set to θ1 = −θ. When the rotating cylindrical portion 32 is joined to the ring portion 30a, the adhesive 320 is applied to the inner peripheral surface of the joining portion of the rotating cylindrical portion 32, and the rotating cylindrical portion 32 is extrapolated to the ring portion 30a as shown in FIG. To do. As described above, the rotating cylindrical portion 32 and the ring portion 30a are joined with a fitting having a tightening margin, and when the rotating cylindrical portion 32 is extrapolated to the ring portion 30a, the adhesive 320 is placed in the oblique grooves 300 and 301. Enters.

  The adhesive 320 is distributed between the inner peripheral surface of the rotating cylindrical portion 32 and the outer peripheral surface of the ring portion 30a and in the groove. The adhesive 320 bonds the rotating cylindrical portion 32 and the ring portion 30a. Will be. In addition, the area | region 303 in which the diagonal grooves 300 and 301 are not formed of the ring part 30a is an inlay part area | region which functions as an inlay part, Thereby, the improvement of the coaxiality of the rotation cylindrical part 32 and the ring part 30a can be aimed at. .

  The groove depth of the oblique grooves 300 and 301 is such that the adhesive hardened in the oblique grooves 300 and 301 even when the rotating cylindrical portion 32 is loosened relative to the ring portion 30a even at a minus temperature in a cold region that is normally assumed. Is set so as to be locked in the oblique grooves 300 and 301 on the ring portion 30a side. For example, it is set to 0.1 to 0.2 mm.

  As shown in FIG. 2, by providing the inclined grooves 300 and 301 having different inclinations, the rotating cylinder with respect to the ring portion 30a is provided even when the rotating cylinder portion 32 is loosened with respect to the ring portion 30a at a low temperature. It is possible to prevent the portion 32 from shifting.

  Here, each function and effect of the oblique grooves 300 and 301 will be described. The adhesive strength of the adhesive 320 is more strongly bonded to the rotating cylindrical portion 32 formed of fiber reinforced plastic than to the ring portion 30a formed of aluminum alloy. Since the oblique groove 300 is formed up to the lower end of the ring portion 30a, when the rotating cylindrical portion 32 is loosened at a low temperature, the rotating cylindrical portion 32 has the adhesive 320 in the groove only in the groove extending direction D1 of the oblique groove 300. It becomes possible to shift. That is, the rotating cylindrical portion 32 moves in the axial direction D12 while rotating in the D11 direction. On the other hand, the upper end of the oblique groove 300 is not opened and is stopped in the middle of the ring portion 30a. Therefore, a shift in the upper right direction of the rotating cylindrical portion 32, that is, a shift in the minus D11 direction and the minus D12 direction is prevented.

  On the contrary, when only the oblique groove 301 is formed, the rotating cylindrical portion 32 allows the adhesive 320 in the groove to shift only in the groove extending direction D2 of the oblique groove 301. That is, when the rotating cylindrical portion 32 is loosened relative to the ring portion 30a, the rotating cylindrical portion 32 is displaced in the axial direction D12 while rotating in the direction D21 opposite to D11.

  However, in the example shown in FIG. 2, since both the oblique grooves 300 and 301 are formed, even if the rotating cylindrical portion 32 is loosened, the deviation in the D11 direction is prevented by the oblique groove 301, and the D12 direction The deviation is prevented by the oblique groove 300. As a result, the rotation cylindrical portion 32 is prevented from rotating relative to the ring portion 30a, and axial displacement is also prevented.

  FIG. 3 is a diagram showing a modification of the embodiment shown in FIG. In this modification, the pitch in the circumferential direction of the oblique grooves 300 and 301 is made smaller than that in the case of FIG. 2, and the oblique grooves 300 and 301 intersect with each other. In this case, since the number of diagonal grooves increases, the effect of preventing deviation is further increased.

  FIG. 4A shows a case where an oblique groove 301 and a ring groove 304 are formed as two types of grooves having different angles. As described above, the oblique groove 301 allows a shift in the D2 direction (D21 and D12 directions) with respect to the rotating cylindrical portion 32. However, since the ring groove 304 is formed, displacement of the rotating cylindrical portion 32 in the axial direction J (D12 direction) is prevented. That is, even when the rotating cylindrical portion 32 is loosened relative to the ring portion 30a, the rotating cylindrical portion 32 cannot be displaced in either the rotational direction or the axial direction.

  Further, in the example shown in FIG. 4B, the angle of the oblique groove 301 in FIG. 4A is 90 degrees, and the ring groove 304 and the groove 305 extending in the axial direction are formed. In this case, the groove 305 prevents the rotational cylindrical portion 32 from shifting in the rotational direction, and the ring groove 304 prevents axial displacement.

  FIG. 5 is a diagram illustrating a second example of the bonding structure. In the second example, the groove filled with the adhesive 320 is constituted by one kind of oblique groove, and the shape of the oblique groove is a spiral groove (screw groove). In the example shown in FIG. 5A, the spiral groove is formed by an equal lead screw groove 306, and in the example shown in FIG. 5B, the spiral groove is formed by a variable lead screw groove 307.

  In the case of the configuration shown in FIG. 5A, inlay portion regions 303a and 303b in which no groove is formed are formed at both ends in the axial direction of the groove forming region 308 in which the thread groove 306 of the equal lead is formed. . That is, the upper end and the lower end of the screw groove 306 are not opened like the lower end of the oblique groove 301 shown in FIG. 4 and are in contact with the groove-free regions (inlay portion regions 303a and 303b). As a result, the adhesive 320 in the groove is blocked by the screw groove 306 in both the rotational direction and the axial direction. As a result, the rotating cylindrical portion 32 fixed to the adhesive 320 in the thread groove 306 cannot be displaced in the axial direction or the rotational direction with respect to the ring portion 30a.

  On the other hand, in the case of the thread groove 307 of the variable lead shown in FIG. 5B, since the inclination of the thread groove 307 changes, as a result, the two types of oblique grooves shown in FIG. 2 are provided. Has the same effect as. In other words, the single cylindrical groove 307 prevents the rotating cylindrical portion 32 from shifting in the rotational direction and the axial direction. Therefore, in the case of FIG. 5B, the inlay portion region 303 for providing the coaxiality is formed only on one side of the groove forming region 308 in which the thread groove 307 of the variable lead is formed.

  FIG. 6 is a diagram illustrating a third example of the bonding structure. Fig.6 (a) is a figure which shows a junction part, FIG.6 (b) is CC sectional drawing. In the third example, a plurality of one type of oblique grooves 309 are formed in the ring portion 30a. As shown in FIG. 6B, the oblique groove 309 has an open lower end in the groove extending direction, but has a shallow groove depth from the upper end to the lower end. That is, the solidified adhesive 320 in the groove cannot be shifted obliquely upward in the groove extending direction because the upper end of the oblique groove 309 is interrupted in the middle, whereas the groove depth becomes shallower as the groove depth approaches the lower end. Therefore, it cannot be shifted obliquely downward in the groove extending direction. Therefore, by adopting such a configuration, even when the rotating cylindrical portion 32 is loosened with respect to the ring portion 30a, the rotating cylindrical portion 32 is not detached.

  In the example shown in FIG. 6, a plurality of oblique grooves 309 are provided, but even one has an effect of preventing deviation.

  FIG. 7 is a diagram illustrating a fourth example of the bonding structure. Fig.7 (a) is a figure which shows a junction part, FIG.7 (b) is EE sectional drawing. In the fourth example, a plurality of arc-shaped grooves 310 that are horizontal in the axial direction are arranged in the circumferential direction of the ring portion 30a. Each groove 310 has surfaces 310a and 310b orthogonal to the axial direction and surfaces 310c and 310d extending in the axial direction. Therefore, the solidified adhesive 320 in the groove is prevented from being displaced in the axial direction by the surfaces 310a and 310b, and is prevented from being displaced in the circumferential direction by the surfaces 310c and 310d. As a result, the rotating cylindrical portion 32 fixed to the adhesive 320 cannot be displaced in the axial direction or the circumferential direction (rotating direction) with respect to the ring portion 30a.

  In the example shown in FIG. 7, a plurality of arc-shaped grooves 310 are provided, but the same effect can be obtained even if one is provided.

  As described above, in the present embodiment, in the turbo molecular pump including the rotating cylindrical portion 32 of fiber reinforced plastic bonded so as to be extrapolated to the ring portion 30a formed at one end of the rotor 30 in the axial direction, At least one groove filled with the adhesive 320 is formed on the outer peripheral surface of the ring portion 30a, which is an adhesive portion on the side of the portion 30a, like the oblique grooves 300 and 301 in FIG. 2 and the groove 310 in FIG. ing. Therefore, since the adhesive 320 solidified and fixed to the rotating cylindrical portion 32 has entered the groove, even if the rotating cylindrical portion 32 may be loosened at a low temperature, the rotating cylindrical portion 32 with respect to the ring portion 30a. There is no slippage.

  For example, as shown in FIGS. 2 to 4, by forming two types of grooves having different angles with respect to the axial direction J in the ring portion 30 a, it is possible to prevent the rotation cylindrical portion 32 from being displaced.

  Further, as shown in FIG. 5, by providing the inlay portion regions 303a and 303b in contact with both axial ends of the groove forming region 308 in which the screw grooves 306 that are oblique grooves are formed, that is, the inlay portion regions 303a and 303b. By forming the screw groove 306 in the groove forming region 308 sandwiched between the two, the screw groove 306 becomes a double-ended groove. Therefore, the adhesive 320 cannot be removed in the screw groove 306, and as a result, the rotating cylindrical portion 32 fixed to the adhesive 320 is prevented from shifting.

  Furthermore, as shown in FIG. 6, the oblique groove 309 is an oblique groove formed so that the groove depth decreases from one end to the other end in the extending direction of the groove, The inlay portion region 303 may be provided in contact with the groove forming region 308 in the axial direction. As a result, the downward displacement of the rotating cylindrical portion 32 in the axial direction is prevented because the groove depth becomes shallower on the lower side. Further, since the oblique groove 309 is cut there by the inlay part region 303, the axial displacement of the rotating cylindrical part 32 is prevented by the groove end surface of the cut part.

  The above description is merely an example, and when interpreting the invention, there is no limitation or restriction on the correspondence between the items described in the above embodiment and the items described in the claims.

  1: turbo molecular pump, 22: fixed blade, 24: screw stator, 30: rotor, 30a: ring portion, 30b: rotating blade, 31: shaft, 32: rotating cylindrical portion, 300, 301, 309: oblique groove, 303, 303a, 303b: Inlay region, 304: Ring groove, 305, 310: Groove, 306, 307: Screw groove, 308: Groove formation region, 320: Adhesive

Claims (5)

A metal rotor in which a multi-stage rotor blade is formed and a ring portion is formed at one end in the axial direction;
A plurality of stages of stationary blades alternately arranged in the axial direction with respect to the rotor blades;
A rotating cylindrical portion formed of fiber reinforced plastic and bonded to be extrapolated to the ring portion;
A fixed cylindrical portion disposed on the outer peripheral side of the rotating cylindrical portion via a gap,
The turbo molecular pump according to claim 1, wherein an adhesive is filled in an adhesive portion of the ring portion, and at least one groove for preventing displacement of the rotating cylindrical portion is formed. The turbo-molecular pump according to claim 1,
The turbo molecular pump according to claim 1, wherein the ring portion is formed with two kinds of grooves having different angles with respect to an axial direction. The turbo-molecular pump according to claim 2,
One of the two types of grooves is a ring groove that goes around the ring portion. The turbo-molecular pump according to claim 1,
The groove is an oblique groove inclined with respect to the axial direction;
The ring part is
A groove forming region in which the oblique grooves are formed;
A turbo molecular pump comprising: an inlay portion region provided in contact with both axial ends of the groove forming region and functioning as an inlay portion with respect to the rotating cylindrical portion. The turbo-molecular pump according to claim 1,
The groove is inclined with respect to the axial direction, and is an oblique groove formed so that the groove depth decreases from one end to the other end in the extending direction of the groove,
The ring part is
A groove forming region in which the oblique grooves are formed;
A turbo molecular pump comprising: an inlay portion region which is provided on the one end side of the oblique groove and is in contact with an axial direction of the groove forming region and functions as an inlay portion with respect to the rotating cylindrical portion.

Images